Hood structure for vehicle

INCORPORATION BY REFERENCE

0001The disclosure of Japanese Patent Application No.2003-365731 filed on Oct. 27, 2003 including the specification, drawings and abstract is incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

00021. Field of the Invention

0003The invention relates to a hood structure for a vehicle, and more particularly to a hood structure for a vehicle, which is applied to a vehicle such as an automobile.

00042. Description of the Related Art

0005Japanese Patent Laid-Open Publication No. 8-80873 (JP-A-8-80873) discloses an example of a hood structure for a vehicle, which is applied to a vehicle such as an automobile. In the hood structure for a vehicle, a hood inner panel is provided on a rear surface side of a hood outer panel including a convex side flat portion and a concave side flat portion between which a level difference portion is provided, and a shock absorbing body is provided between the hood outer panel and the hood inner panel. The shock absorbing body is supported by the hood inner panel, and supports, from the rear surface side, the convex side flat portion in the vicinity of the level difference portion. In addition, the shock absorbing body is deformed and collapsed so that desired reaction force is generated when a displacement of the hood becomes a predetermined value.

0006However, in the hood structure for a vehicle disclosed in the Japanese Patent Laid-Open Publication No. 8-80873, the separate shock absorbing body needs to be provided between the hood outer panel and the hood inner panel, which leads to an increase in the number of components, an increase in weight, an increase in assembly cost, and deterioration of productivity. Also, when a hitting body hits the hood, incomplete collapse of the shock absorbing body occurs, and a portion of the shock absorbing body which is incompletely collapsed cannot be used as an energy absorbing stroke. Therefore, the energy absorbing stroke becomes small. Also, in the case where there are components such as an engine below the hood, and energy needs to be absorbed efficiently in a limited space, energy absorbing efficiency is reduced.

SUMMARY OF THE INVENTION

0007It is an object of the invention to provide a hood structure for a vehicle which can improve energy absorbing efficiency without providing a separate shock absorbing body even in the case where there is only a limited space.

0008A first aspect of the invention relates to a hood structure for a vehicle, which includes a hood outer panel constituting a vehicle body outer side portion of a hood; a hood inner panel constituting a vehicle body inner side portion of the hood; a level difference portion that is formed on the hood outer panel along a longitudinal direction of a vehicle; several bone portions that are formed in the hood inner panel along the longitudinal direction of the vehicle at predetermined intervals in a vehicle width direction; and a flange that connects adjacent bones among the several bones at a portion below the level difference portion.

0009Thus, the several bone portions are formed in the hood inner panel along the longitudinal direction of the vehicle at the predetermined intervals in the vehicle width direction, and the flange connects the adjacent bones among the several bones at the portion below the level difference portion. Therefore, the level difference portion has a double structure composed of the hood outer panel and the hood inner panel. As a result, torsional rigidity of the hood is improved. In addition, when a hitting body hits the vicinity of the level difference portion of the hood outer panel, the hood outer panel is unlikely to be inverted toward a lower side of the vehicle. Accordingly, since a primary peak value of an acceleration applied to the hitting body can be increased without providing a separate shock absorbing body. Since the separate shock absorbing body does not need to be provided, the amount of incomplete collapse can be reduced by the amount of incomplete collapse of the separate shock absorbing body. Thus, energy can be absorbed efficiently even in the case where there is only a limited space.

0010In the first aspect of the invention, the flange may be formed such that a cross section of the flange in the longitudinal direction of the vehicle is a straight line.

0011Thus, in addition to the structure in the first aspect, the cross section of the flange in the longitudinal direction of the vehicle is a straight line. Therefore, the flange is not inverted when the hitting body hits the vicinity of the level difference portion of the hood outer panel, and accordingly there is no excess stroke due to inversion of the flange. As a result, since tensile force is generated in the flange immediately after the hitting body hits the vicinity of the level difference portion of the hood outer panel, the primary peak value can be generated early.

0012In the first aspect of the invention, reinforcement means for improving surface rigidity may be formed in the flange.

0013Thus, in addition to the structure in the first aspect, the reinforcement means improves the surface rigidity of the flange. As a result, the flange is unlikely to be inverted when the hitting body hits the vicinity of the level difference portion of the hood outer panel, and stress is propagated to the bone portions easily. Accordingly, the primary peak value can be further increased, and the rigidity of the hood itself can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

0014<figref idref="DRAWINGS">FIG. 1</figref> is an enlarged cross sectional view taken along line I—I in <figref idref="DRAWINGS">FIG. 3</figref>;

0015<figref idref="DRAWINGS">FIG. 2</figref> is a cross sectional view showing a deformed state of a hood structure for a vehicle according to an embodiment of the invention, which corresponds to FIG <b>1</b>;

0016<figref idref="DRAWINGS">FIG. 3</figref> is a plan view showing the hood structure for a vehicle according to the embodiment of the invention, which is seen from below a vehicle body;

0017<figref idref="DRAWINGS">FIG. 4</figref> is a perspective view showing a food outer panel of the hood structure for a vehicle according to the embodiment of the invention, which is seen obliquely from ahead of the vehicle body;

0018<figref idref="DRAWINGS">FIG. 5</figref> is a graph showing a relation between a stroke of a hitting body and an acceleration in the hood structure for a vehicle;

0019<figref idref="DRAWINGS">FIG. 6</figref> is a cross sectional view showing a hood structure for a vehicle according to another embodiment of the invention, which corresponds to <figref idref="DRAWINGS">FIG. 1</figref>;

0020<figref idref="DRAWINGS">FIG. 7</figref> is a cross sectional view showing a deformed state of the hood structure for a vehicle according to another embodiment of the invention, which corresponds to <figref idref="DRAWINGS">FIG. 6</figref>; and

0021<figref idref="DRAWINGS">FIG. 8</figref> is a perspective view showing a portion of the hood structure for a vehicle according to a yet another embodiment of the invention, which is seen obliquely from the outside of the vehicle body in a direction from a rear side toward a front side of the vehicle body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

0022Hereinafter, a hood structure for a vehicle according to an embodiment of the invention will be described with reference to <figref idref="DRAWINGS">FIG. 1</figref> to <figref idref="DRAWINGS">FIG. 5</figref>.

0023In each of drawings, an arrow UP indicates an upward direction of a vehicle body, an arrow FR indicates a forward direction of the vehicle body, and an arrow IN indicates an inward direction of a vehicle width.

0024As shown in <figref idref="DRAWINGS">FIG. 3</figref>, a hood <b>10</b> according to the embodiment includes a hood outer panel <b>12</b> and a hood inner panel <b>14</b>. The hood outer panel <b>12</b> constitutes a vehicle body outer side surface of the hood <b>10</b>. The hood inner panel <b>14</b> is provided on the inner side (i.e., on the rear surface side) of the hood outer panel <b>12</b>, and constitutes a vehicle body inner side portion of the hood <b>10</b>.

0025As shown in <figref idref="DRAWINGS">FIG. 4</figref>, level difference portions (relief portions) <b>16</b> are formed in the vicinity of vehicle-width-direction both ends of the hood outer panel <b>12</b> along a longitudinal direction of the vehicle body. Each of the level difference portions <b>16</b> is formed from a portion the hood outer panel <b>12</b> which is in a front side of the vehicle body and which is in an inner side in the vehicle width direction to a portion of the hood outer panel <b>12</b> which is in a rear side of the vehicle body and which is in an outer side in the vehicle width direction.

0026As shown in <figref idref="DRAWINGS">FIG. 3</figref>, several bone portions <b>18</b> are formed along the longitudinal direction of the vehicle at predetermined intervals in the vehicle width direction in a center region <b>14</b>E of the hood inner panel <b>14</b>. The center region <b>14</b>E is a region other than a front edge portion <b>14</b>A, a rear edge portion <b>14</b>B, right and left vehicle-width-direction outer side line portions <b>14</b>C and <b>14</b>D of the hood inner panel <b>14</b>, which are outer peripheral portions of the hood inner panel <b>14</b>. A bone portion <b>20</b> is formed along the longitudinal direction of the vehicle at each vehicle-width-direction inner side portion which is positioned inside each of the vehicle-width-direction outer side line portions <b>14</b>C and <b>14</b>D.

0027Also, a notch <b>21</b> is formed between adjacent bone portions <b>18</b>. Several adhesive agent application portions <b>22</b> are formed in an outer peripheral portion of the notch <b>21</b>.

0028As shown in <figref idref="DRAWINGS">FIG. 1</figref>, vehicle-width-direction both ends <b>12</b>A of the hood outer panel <b>12</b> are joined to vehicle-width-direction both ends <b>14</b>F of the hood inner panel <b>14</b> by hemming process.

0029Each of the bone portions <b>20</b> of the hood inner panel <b>14</b> protrudes toward a lower side of the vehicle body. A reinforcement <b>26</b> for a hood hinge is provided on an upper surface side of a bottom portion <b>20</b>A of the bone portion <b>20</b>. Meanwhile, each of the bone portions <b>18</b> formed in the center region <b>14</b>E of the hood inner panel <b>14</b> protrudes toward the lower side of the vehicle body. A flange <b>30</b> that connects the bone portion <b>18</b> and the bone portion <b>20</b> is formed at a portion below the level difference portion <b>16</b> of the hood outer panel <b>12</b>.

0030The flange <b>30</b> of the hood inner panel <b>14</b> extends so as to be curved along the level difference portion <b>16</b> of the hood outer panel <b>12</b>. The flange <b>30</b> of the hood inner panel <b>14</b> is joined to the level difference portion <b>16</b> of the hood outer panel <b>12</b> through an adhesive agent <b>32</b> applied to the adhesive agent application portion <b>22</b>. Also, engine room components <b>36</b> such as an engine are provided below the flange <b>30</b> of the hood inner panel <b>14</b>.

0031Although the structure of the vehicle-width-direction outer side line portion <b>14</b>C of the hood inner panel <b>14</b> is not shown, it is the same as that of the vehicle-width-direction outer side line portion <b>14</b>D of the hood inner panel <b>14</b> shown in <figref idref="DRAWINGS">FIG. 1</figref>.

0032Next, effects of the embodiment will be described.

0033In the embodiment, the flange <b>30</b> that connects the bone portion <b>18</b> and the bone portion <b>20</b> is formed at the portion below the level difference portion <b>16</b> of the hood outer panel <b>12</b>. The hood <b>10</b> has a double structure composed of two panels, that is, the hood outer panel <b>12</b> and the hood inner panel <b>14</b>. As a result, torsional rigidity of the hood <b>10</b> is improved. Also, as shown in <figref idref="DRAWINGS">FIG. 2</figref>, when a hitting body K hits the level difference portion <b>16</b> of the hood outer panel <b>12</b>, the level difference portion <b>16</b> of the hood outer panel <b>12</b> is unlikely to be inverted toward the lower side of the vehicle.

0034Therefore, as shown by a solid line in <figref idref="DRAWINGS">FIG. 5</figref>, in a change in an acceleration G applied to the hitting body K (acceleration characteristic G) with respect to a stroke S of the hitting body K, a primary peak value P<b>1</b> can be increased such that energy can be absorbed when a speed of the hitting body K is high, and a secondary peak value P<b>2</b> can be decreased in the embodiment, as compared to an acceleration characteristic G<b>1</b> shown by a dashed line in <figref idref="DRAWINGS">FIG. 5</figref> in a comparative example in which the flange <b>30</b> is not formed. Accordingly, in the hood structure for a vehicle according to the embodiment, energy can be absorbed efficiently in a given space without providing a separate shock absorbing body.

0035Since a separate shock absorbing body does not need to be provided between the hood outer panel <b>12</b> and the hood inner panel <b>14</b>, it is possible to prevent an increase in the number of components, an increase in weight, and an increase in assembly cost. In addition, incomplete collapse of the shock absorbing body does not occur. As a result, even when there is only a limited space, energy can be absorbed efficiently using the limited space effectively.

0036Also, since a separate shock absorbing body does not need to be provided between the hood outer panel <b>12</b> and the hood inner panel <b>14</b>, the thickness of the hood <b>10</b> is small. As a result, a distance L between the hood inner panel <b>14</b> and the engine room components <b>36</b> such as the engine below the hood is large, and a secondary hit on the engine room components <b>36</b> can be prevented.

0037Also, in the embodiment, since the level difference portion <b>16</b> of the hood outer panel <b>12</b> is joined to the flange <b>30</b> of the hood inner panel <b>14</b> by the adhesive agent <b>32</b>, tensile rigidity of the hood <b>10</b> is also improved.

0038The specific embodiment of the invention has been described in detail so far. However, the invention is not limited to the embodiment. It is apparent to persons skilled in the art that the invention can be realized in various embodiments. For example, the flange <b>30</b> of the hood inner panel <b>14</b> extends so as to be curved along the level difference portion <b>16</b> of the hood outer panel <b>12</b>, as shown in <figref idref="DRAWINGS">FIG. 1</figref>. Instead, as shown in <figref idref="DRAWINGS">FIG. 6</figref>, the flange <b>30</b> of the hood inner panel <b>14</b> may be formed such that the cross section of the flange <b>30</b> is a straight line in the longitudinal direction of the vehicle body. In this case, the flange <b>30</b> is not inverted when the hitting body hits the level difference portion <b>16</b> of the hood outer panel <b>12</b>, and accordingly there is no excess stroke due to inversion of the flange <b>30</b>, as shown in <figref idref="DRAWINGS">FIG. 7</figref>. As a result, tensile force is generated in the flange <b>30</b> immediately after the hitting body K hits the level difference portion <b>16</b> of the hood outer panel <b>12</b>. Therefore, the primary peak value P<b>1</b> of the acceleration can be generated early as compared to the acceleration characteristic G shown by the solid line in <figref idref="DRAWINGS">FIG. 5</figref>. Accordingly, even in the case where there is only a limited space, energy can be absorbed efficiently using the limited space effectively.

0039Also, as shown in <figref idref="DRAWINGS">FIG. 8</figref>, a bead <b>50</b> that is reinforcement means (a reinforcement portion) for connecting the bone portion <b>18</b> and the bone portion <b>20</b> for improving surface rigidity may be provided in the flange <b>30</b> of the hood inner panel <b>14</b>. In this case, since the bead <b>50</b> improves the surface rigidity of the flange <b>30</b>, the flange <b>30</b> is more unlikely to be inverted, and stress is propagated to the bone portion <b>18</b> and the bone portion <b>20</b> more easily when the hitting body K hits the level difference portion <b>16</b> of the hood outer panel <b>12</b>. As a result, the primary peak value P<b>1</b> of the acceleration can be further increased, and the rigidity of the hood <b>10</b> itself can be improved, as compared to the acceleration characteristic G shown by the solid line in <figref idref="DRAWINGS">FIG. 5</figref>. Accordingly, even in the case where there is only a limited space, energy can be absorbed efficiently using the limited space effectively.

0040In the aforementioned embodiment, each of the level difference portions <b>16</b> is formed in the vicinity of each of vehicle-width both ends of the hood outer panel <b>12</b>, from the portion which is in the front side of the vehicle body and which is in the inner side in the vehicle width direction to the portion which is in the rear side of the vehicle body and which is in the outer side in the vehicle width direction. However, in the case where each of the level difference portions <b>16</b> is formed on the hood outer panel <b>12</b> at another portion, the hood structure for a vehicle according to the invention can be applied.

0041Also, an opening portion may be formed in the flange <b>30</b> of the hood inner panel <b>14</b> in order to reduce weight.